Time-clustering analysis of volcanic occurence sequences

We investigate the time dynamics of worldwide volcanic activity in order to find the presence of time correlation structures, by applying the Fano factor (FF) method. The analysis, performed on 35 time-occurrence volcanic eruptive sequences with volcanic explosivity index (VEI greater than or equal to 0) has revealed fractal behaviors in the most of the data sets considered, with fractal exponent a ranging from similar to0.2 to 0.9.